2nd o2 sensor

[twlplague]

why does the stock cat have two o2 censors?
1 in the back and 1 in the front... is the back one that important?

i got a test pipe and it does not have a hole for the 2nd o2 censor.

 

[nautica_t]

there's a read up on how o2 sensors work, but if you throw that test pipe on you'll throw a CEL code, and you're car will run richer and you'll be stinky with gas smells because you're now rich.

 

[newspeed]

why does the stock cat have two o2 censors?
1 in the back and 1 in the front... is the back one that important?

i got a test pipe and it does not have a hole for the 2nd o2 censor.

the downstream o2 sensor (one after cat) measures the efficiency of the cat. when i was putting my exhaust on we had to torch some bolts and accidently heated the o2 sensor causing a CEL. however this has not effected perfomance. so you might be able to leave it out and live with the cel

 

[nautica_t]

you're car won't run as efficient without the secondary o2. cause the secondary like you said checks the efficiency of the cat. the primary gets a reading and if its not relevent to the second than it'll correct the mixture pending on what needs to be adjusted. but without it'll keep running rich from my understanding.

 

[twlplague]

hmmm...i need more imput lol...two people....two opposing views
thanks though!!!

 

[TegSox]

I don't see how the engine can be completely unaffected when it's 2nd O2 sensor is suddenly gone. I wouldn't just take it out and leave it at that, live with a CEL?, screw that! I say just spend the 20 bucks at a muffler shop and have an O2 bung put in your testpipe, problem's solved.

 

[twlplague]

ya that is what i was really leanin towards...i just didnt know if the only reason for that o2 censor was to see if your cat was working

 

[nautica_t]

I don't see how the engine can be completely unaffected when it's 2nd O2 sensor is suddenly gone. I wouldn't just take it out and leave it at that, live with a CEL?, screw that! I say just spend the 20 bucks at a muffler shop and have an O2 bung put in your testpipe, problem's solved.

tegsox even if he welded another o2 sensor bung he'll still throw a code.

 

[TegSox]

Oh yeah, were talking about a test pipe here, doh! :smackself

Sorry, I can't help you on doing an O2 bypass, cuz:
-I'm OBD1
-I would never use a test pipe for any reason anyway, so I would never have the need to learn how to bypass an O2 sensor, or an O2 censor for that matter.

Get a high flow cat! There, NOW the problem's solved, lol.
-no stinky exhaust
-no CEL
-no O2 bypass needed
-you'll pass emmissions/inspection
-no chance of huge fines, cuz we all know test pipes aern't street legal
-it's good for the planet, you'll feel better about yourself for doing the right thing.

Boy, all kinds of problems get solved by using a high flow cat.

 

[mteg]

If you want to bypass the 2nd O2 sensor, you need to buy an O2 simulator. You can find them on E-bay for about $20. If you don't use one your car will throuw a code and will go into a "limp" mode becuase it thinks something is wrong.